Juniata Chemist Focuses on Fingerprint Technology

(Posted April 22, 2002)

HUNTINGDON, Pa. -- The crusading forensic sleuths on such television shows as "CSI" and "Crossing Jordan" seemingly can solve crimes by lifting fingerprints from such exotic surfaces as toenails, leather upholstery and even human skin. In the real world of crime solving, it's no sure bet that fingerprints can be identified from porous surfaces such as paper, but a Juniata College chemistry professor and a team of students are working to improve those odds.

"In the movies and on detective shows, the police are always dusting for prints, but application of a fine powder to reveal fingerprints only works on nonporous surfaces such as glass, Formica and painted areas," says Richard Hark, associate professor of chemistry at Juniata. "Identifying fingerprints on porous surfaces such as paper, wallpaper and other areas must be done by using a chemical substance that makes the print visible to investigators."

Hark and Juniata student Angela Sauers, a senior from York Springs, Pa., are working to create an improved chemical reagent that can easily be applied by investigators at a crime scene or in a forensic lab and that has properties that allows technicians to see the print more easily under laser light.

"A fingerprint is approximately 99 percent water and the remaining 1 percent contains oils, salts, amino acids and other components," Hark explains. When a finger touches a surface these residues remain on that surface, leaving an invisible print called a "latent" fingerprint. Currently, law enforcement investigators use a chemical compound called ninhydrin to spray on latent prints. Ninhydrin causes the amino acid residues in the fingerprint to appear purple. Forensic technicians also use other chemicals to cause latent prints to glow or "fluoresce" when exposed to various light sources.

Hark and Sauers are working to create a compound with enhanced features based on compound called 1,2-indanedione, which has excellent fluorescing properties. Their research is derived from Hark's doctoral research at the University of Pennsylvania, where he developed several chemical compounds related to ninhydrin -- called "analogs" in chemistry circles. Earlier in his research career, Hark collaborated with the U.S. Secret Service on the development of latent fingerprint reagents.

"The Secret Service is particularly interested in this type of research because much of their work focuses on porous surfaces like counterfeit currency, forged checks or threatening letters to government officials," Hark says.

Sauers, one of several undergraduates working on fingerprint research in Hark's laboratory, uses synthetic organic chemistry techniques to create the new compound. While most of her time is spent mixing and analyzing chemicals rather than discovering fingerprints, Sauers is intrigued by the practical applications of her research. So far, her synthesis of the fluorescing compound is on track, but there is no guaranteeing success at the end of the road.

"Doing a chemical synthesis is like planning a trip," Hark says. "You have to make sure of every stop, but if a bridge is out, you have to find an alternate way to your destination."

If Sauers' synthetic compound is a marked improvement over current reagents, then Hark will assign other students to discover if the compound can be produced economically. "There is so much interest in forensic science now that this research not only is a rare opportunity for our undergraduates, but becomes a great way to see how chemistry techniques can be used to solve a problem," Harks says.